The present invention relates generally to the art of food packaging and more particularly to a container for packaging, storing, displaying and heating food.
Containers of the type disclosed herein are well known in the art. They are low in cost, disposable and are adapted to protect the food packaged therein under various temperature conditions. Moreover, such containers are capable of being formed on high speed equipment. However, the prior art does not disclose a container which incorporates all of the features of the present invention.
For example, considering exemplary prior art patents, U.S. Pat. No. 3,917,155 discloses a laminated package in the form of a flanged, open top tray with an integral lid. Containers formed in accordance with the teachings of this patent are acceptable for most purposes, but once these containers are formed, they are difficult to store because their side walls are straight and are all of the same dimensions. Thus, users of the container disclosed in U.S. Pat. No. 3,917,155 must also have forming equipment so the containers can be formed and filled in line without intermediate storage. Meanwhile, U.S. Pat. No. 4,019,675 which also shows a flanged, open top tray with an integral lid, overcomes the storage problems of the aforementioned patented construction by making the side walls divergent to achieve a nest. However, after being filled, the containers formed in accordance with the teachings of U.S. Pat. No. 4,019,675 must be displayed horizontally, or, on top of one another because the tapered side walls will not allow the containers to stand along one edge. Thus, while the users of the container disclosed in the latter patent need only have edge sealing equipment, the resulting construction is not versatile from a product storage and display point of view. Finally, other exemplary prior art, including U.S. Pat. Nos. 3,863,832 and 3,865,302, each show two part containers prepared from separate lids and trays, and the container constructions represented by these patents present yet other problems. For instance, when two part containers are selected, the user must keep separate inventories of lids and trays. In addition, special equipment is required for sealing the containers, particularly for correctly aligning the lids with the trays. Moreover, where the trays have divergent side walls, which is generally the case, the options available for storing and displaying the filled containers are limited.
Another problem typical of many of the prior art constructions is the difficulty of removing the lid from the tray when it is desired to serve the food packaged therein. This problem varies with the type of material used to construct the container. Typically, the most severe problems occur with thermoplastic coated paperboard containers when the lid is heat sealed to the tray. With such constructions, the heat seal can be strong enough to require the use of a knife in order to get the lid removed in one piece. Thus, while the prior art discloses a number of container constructions which satisfy one or more of the desirable features required by the users of such food packages, the prior art does not disclose a container which satisfies all of the criteria previously outlined.